Music production, recording, and mixing

Great sounding reverb with just two sends

Great sounding reverb with just two sends

If you have access to a large, great sounding live room, you may not need to worry too much about creating a sense of space: you can control the amount of ambience with microphone placement and additional room mics if necessary.

But if you record in a small room with close microphones, or you’re mostly working with synths, samples, or virtual instruments, it can be tricky to get a sense of ambience without drowning things out in reverb. Delay effects can sound fantastic, but work best when set up on a track-by-track basis, and aren’t as diffuse and dense as a reverb.

In this post I present a very quick way to set up great sounding reverb for a whole track. You’ll probably want to use more specialised reverb and delay effects when it comes to the final mix, but with this two reverb approach you’ll be able to do most of your production work without worrying too much about reverb, or get a working mix done very quickly.

The software

I use Logic Pro X as my main DAW, but this technique will work with any DAW. I will also use two reverb plugins by Valhalla DSP. You don’t have to use these plugins – there are many other reverb plugins that will work just as well. But I personally find that Valhalla reverbs are very good value for money, sound great, and are very easy to use. They also all have zero latency, and usually use very little CPU. Note: I have no affiliation with Valhalla DSP.

Logic Pro X also has some built-in reverb plugins, but these are showing their age. They’re not diffuse enough (the echoes aren’t close enough together) and so they sound a bit grainy to me. Even Logic’s Space Designer convolution reverb sounds grainy to me compared to other convolution reverb plugins, and introduces unnecessary latency.

The “dry” track

For reference, here’s the dry track that we’re starting with, with no reverb or delay of any kind. It’s nothing special, a fairly standard loop created from some virtual synths and samples:

Why two reverbs instead of one?

We want a very short, very dense room ambience reverb that won’t sound like reverb, but gives a source a strong sense that it’s in a “place”. This is known as the early reflections. We also want a longer, but still dense, reverb to provide a natural sounding reverb tail, with a sense of depth and distance. We call this the reverb tail or late reflections.

We could do both of these things on one aux channel and with one reverb plugin. But by having two aux channels, it makes it much easier to find exactly the right amount of early and late reflections we want. For example, there might be some sounds where we want lots of early reflections, but not many late reflections, and vice versa. For some reason, this two reverb approach just makes things feel very easy and quick.

Aux channels, sends, and routing

Before proceeding, if you don’t understand how buses, aux channels, and routing work in Logic Pro X, you should probably read this. Broadly speaking, the way buses and sends work in Logic Pro X is very similar to most other DAWs, and even many mixing consoles.

We’re not putting these reverbs on individual tracks, and we’re not putting them across the master bus. We’re putting them on aux channels, so that we can “send” to them from each of the instrument tracks in our project.

The first reverb: very short and very dense

The first reverb is VERY short, and has lots and lots very dense / diffuse echoes. It won’t really sound like a “reverb”, but will put things in a space. The aux channel for this reverb looks like this:

We start off with the Valhalla Room plugin, with the following settings:

Mix: 100% – As we’re using this reverb on an aux channel, we want it to be 100% wet – ie, we only want to hear the reverb and none of the dry signal.

Predelay: 0.0ms – For now, we’re not using any predelay. But we could always experiment with this setting later.

Decay: 2.00s – The decay setting is irrelevant here, as it only affects the late reflections, and not the early reflections. And we’re only using this plugin for its early reflections.

High cut: 15000 Hz – Valhalla Room provides a high cut (low pass) filter for the reverb, but we don’t want to cut out any high frequencies for now, so we’re leaving this on its highest value.

Depth: 0.0% – Here we come to the important part. Valhalla Room splits the reverb sound into two parts: the early reflections (otherwise known as ambience) and the late reflections (otherwise known as the reverb tail). The depth slider controls the volume balance of these two sections. In our two reverb strategy, we’re only using Valhalla Room for early reflections, which is why we have this set to 0.0%.

Early and Late buttons – The Early and Late buttons allow you to access the parameters for the two different sections of the reverb. We’re only using the Early section here, so that is what I have shown.

Early Size: 80.5ms – This is the size of the simulated room, but expressed as a unit of time instead of as a unit of distance. I find that 80ms just seems to work. If you make this smaller, you can end up with everything sounding like it was recorded in a tiny room, which is the opposite of what we’re trying to achieve here.

Early Cross: 1.00 – This specifies that we want the maximum amount of stereo spread.

Mod Rate and Mod Depth: We’re not using any modulation here, so with Mod Depth set to 0.0 we can ignore Mod Rate. But this is certainly something to experiment with.

Early Send: The value here is irrelevant, as it controls the amount of early reflections sent to the late reflection section, and we’re not using late reflections.

Diffusion: 1.00 – This is a really critical value. If you think of reverb as lots of echoes that are all very close together, then the more diffusion you have, the more echoes you have, and the closer together and denser they are. With more diffusion, reverb sounds smoother, and with less diffusion, reverb sounds “grainier”. Eventually as you get less and less diffuse, you can start to hear the individual echoes.

Reverb diffusion is always important. Reverbs that sound less diffuse are good for sources that don’t have many quick transients, such as vocals and bowed strings. In fact, with those types of sources, a less diffuse reverb can sound better than a more diffuse one, because having fewer individual echoes help give our brain a stronger sense of space. But on sources with lots of very fast transients (drums and percussion, sometimes acoustic guitar), a less diffuse reverb can sound very “grainy”, which is not good.

Why do we want maximum diffusion for our reverb here? Well, we’re trying to use just two reverbs for an entire mix. And since a very diffuse reverb never sounds bad, but a non-diffuse reverb sounds good or bad depending on the source, we’re picking a diffuse reverb because it will work well for all sources.

Reverb Mode: Large Room – This controls the overall algorithm for the reverb. The default value of Large Room works well here, but certainly play around with this.

After Valhalla Room, we have a very simple high pass filter at around 360 Hz using Logic’s built in EQ. You can use any EQ for this. I’m high passing the output of Valhalla Room to make sure that we don’t add any low end muddiness. But you don’t always need to do this, and as always, you should use your ears:

The second reverb: much longer, but still very dense

Here’s the aux channel for our second reverb:

It’s very similar to the channel strip for our first reverb. But we’re using Valhalla Plate instead of Valhalla Room.

Valhalla Plate is an emulation of a plate reverb. I’ve never used a real hardware plate reverb, so I don’t know how accurate an emulation this is. But it’s certainly the best sounding plate reverb I’ve ever used, and it uses very little CPU, has zero latency, has a great user interface, and is very reasonably priced.

Valhalla Plate has a very smooth, diffuse, and dense sound, and generates a fantastic sense of space. There aren’t many parameters, and it’s one of those plugins that seems to sound good whatever you do with it.

Let’s look at how Valhalla Plate is set up:

Mix: 100% – Again, as this is on an aux channel, we want no dry signal.

Predelay: 0.0ms – We don’t want any predelay for now, but we can always add some later.

Decay: 2.0s – This is a good medium decay time for a reverb tail. It’s about 25 times longer than the 80.5ms decay time we’re using in Valhalla Room, clearly demonstrating the two different roles that the reverbs play. There’s no reason to stick to this value, and you should certainly experiment with reverb times until they sound right.

Size and Width: I’ve left these at their default values, which work well. But I would certainly experiment with the size. Width at 100% is important for an overall mix reverb, as below 100% we lose stereo width, and above 100% a big hole opens up in the centre of the mix (and mono compatibility is sacrificed). Different width values could work well on different sources, but for a “whole mix” reverb, 100% is what we want.

EQ: The EQ inside the plugin is flat because I’m using Logic’s EQ afterwards instead.

Modulation: I’m not using any modulation here, but it’s certainly something to experiment with.

MODE: I’ve left it in the default Chrome setting. The mode changes the material that the virtual plate is made out of, effectively controlling how the tone of the reverb changes over time. All of the materials sound great to me, but again this is something to experiment with.

After Valhalla Plate, I’m again using Logic’s built-in EQ to remove some of the low end:

The EQ settings are in fact identical to those I’m using after Valhalla Room, but they don’t have to be, and you should always experiment and use your ears. For example, sometimes sending a sub-bass to a reverb without any filtering can create a cinematic sense of bass width and, despite the internet consensus, low frequencies don’t need to be mono – they just need to be mono compatible.

Sending tracks to the reverb aux channels

Now we want to go through each of the tracks in our project and decide how much to send to each reverb. This is where the magic happens. My general rule is: Less is more. Typically, I’ll start by sending a track to Valhalla Room. I’ll solo the track, increase the send level until I can just about hear the effect, then I’ll add another send to Valhalla Plate, and do the same. Solo’ing the track is useful for being able to hear the changes that you make, but it’s also critical to hear the reverb sends for an individual track in the context of an entire mix.

The results

I tend to send to the two reverbs as I record / produce a song. In this example I’ve sent slightly higher levels than I might usually do, so you can hear the result clearly.

The trick here is that if, overall, you send to Valhalla Room at a higher level than you send to Valhalla Plate, you can get a better sense of space without having things sound too distant. And that’s what I’ve done here.

So for reference, here’s the original dry track, with no reverb or delay:

Using extra aux channels for predelay

Finally, you’ll probably want to add some predelay to some of your reverb sends, especially for vocals. But you don’t need to add another reverb plugin instance to do this. Simply create another aux channel with a delay plugin on it, and then set the output of that aux channel to one of your reverb send buses.

For example, say that bus 30 goes to aux channel 1 with your reverb on it, which outputs to stereo out. Create a new aux channel, say aux channel 2, which receives from bus 31, and has its output as bus 30. Put a delay effect on aux channel 2 with your desired level of predelay. Then when you want reverb with predelay, send to bus 31 instead of bus 30. This concept works with any kind of effect such as EQ, modulation, compression etc.